Into to physiology and resp anatomy(physiology) Flashcards
What are the functions of the respiratory system?
(4)
Gas exchange - O2 added form air (burnt to produce energy and CO2), CO2 removed from blood.
Acid base balance - regulation extracellular pH
Protection from infection - via lymphatic tissue lining the system
Communication via speech - vocal chords vibrate = sounds
Define systemic circulation
Delivers O2 to tissues and CO2 from tissues out of lungs.
Goes round the whole body
Define pulmonary circulation
Delivers CO2 to lungs from heart an O2 from lungs to heart to be pumped round the body
(pulmonary vein = oxygenated blood from lungs to heart)
(pulmonary artery = deoxygenated blood form heart to lungs)
Identify the points of gas exchange between respiratory and cardiovascular systems.
Between alveoli and capillaries. Gas diffuses across the border and enters circulation through pulmonary capillaries.
What are the main anatomical features of the respiratory system (airways and lungs)?
Upper Tract
Nasal cavity - main breathing organ, cilia and mucus trap particles and warm/moisten the air
Pharynx - shared with digestive system
Epiglottis - small flap of tissue fold over the trachea and prevents food from entering when you swallow.
Larynx - voice box, contains vocal chords which vibrate to produce sound when you exhale.
Lower Tract
Trachea - Air from upper tract moves down trachea to lungs, its made up of rings of cartilage that support and protect it.
Bronchus - Trachea splits to form right/left bronchus, splits again into bronchi (3 in right = 3 lobes, 2 in left = 2 lobes), keeps splitting etc.
Lungs - Soft/spongy, filled with alveoli.
Why is there resistance to airflow throughout the respiratory tree?
Resistance increases in upper tract and in area of decreased diameter.
Most resistance in upper airways
(total cross sectional area of bronchial is greater than trachea as we have many more of them) therefore more space for air to flow even though individually they are smaller.
What can increase/decrease resistance?
Airway diameter (is dynamic)
- Can contract and relax
- Resistance will increase with contraction, decrease with relaxion
(asthma = inappropriate contraction of smooth muscle in airways = greater resistance)
Define alveoli and their role
Alveoli are located at the termination of bronchioles
Role - Gas exchange (via diffusion)
Have a rich capillary network wrapped around the alveoli which allow for gas exchange.
What are the 2 types of alveoli cells and what are their functions?
Type 1
- Participate in gas exchange
- Thin and make up bulk of the alveoli
Type 2
- Produce surfactant which reduces surface tension of alveoli and stop them from collapsing.
- Makes work of breathing easier as alveoli don’t have to be inflated from collapse each time.
What makes up the spaces?
Connective tissue (elastic fibres)
Capillaries (in direct contact with type 1 cells)
Macrophages (attack inhaled pathogens)
Why can gas exchange only occur in alveoli?
Upper airways are too thick for gas exchange, gas cannot diffuse through wall.
What is the air in conduction airways called?
Anatomical dead space - not involved in gas exchange
